The defense in Andrea Yates' murder trial rested Tuesday after her best friend tearfully told jurors that the woman who drowned her five children in the bathtub "misses them terribly."

Debbie A. Holmes, who met Yates about 20 years ago when both were nurses at the University of Texas M.D. Anderson Cancer Center, said she still visits Yates and writes her letters.

Yates, 42, is being retried in her children's 2001 bathtub drowning deaths because her capital murder conviction was overturned by an appeals court that ruled erroneous testimony might have influenced the jury. She has again pleaded not guilty by reason of insanity.

Her attorneys say she suffered from severe postpartum psychosis and did not know it was wrong to kill 7-year-old Noah, 5-year-old John, 3-year-old Paul, 2-year-old Luke and 6-month-old Mary.

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Prosecutors began their rebuttal case Tuesday. They have said they plan to call Dr. Park Dietz, the psychiatrist whose testimony led to Yates' conviction being overturned.

Dietz, also a "Law & Order" television series consultant, told the first jury that in one episode of the crime drama a woman was acquitted by reason of insanity after drowning her children in a tub. He said the show aired before the Yates children died. But after her 2002 conviction, it was discovered no such episode existed.

Holmes testified that Yates was a sweet friend, dedicated nurse and loving mother, but that after the birth of her fourth son she turned into a "total zombie" who stared into space and couldn't finish sentences.

Holmes said she helped care for her friend's children in 1999 after Yates returned from a psychiatric hospital following two suicide attempts. Holmes said that a few months later she asked Yates why she had been so depressed.

"She asked me if I thought Satan could read her mind and if I believed in demon possession," Holmes said.

Earlier Tuesday, prosecutors cross-examined a neuropsychologist who evaluated Yates about six months after the drownings.

Dr. George Ringholz said Yates recounted a hallucination she had after the birth of her first child.

"What she described was feeling a presence ... Satan ... telling her to take a knife and stab her son Noah," Ringholz said.

Ringholz acknowledged that he did not perform certain tests to see if Yates was trying to make her mental illness appear worse, but he said other tests and safeguards as part of the extensive two-day evaluation indicated she was not faking. Ringholz diagnosed schizophrenia.

Ringholz said Yates was delusional the day of the drownings and did not know her actions were wrong, even though she called 911 and knew she would be arrested. Her delusion was that Satan had entered her and that she had to be executed in order to kill Satan, he said.

"Delusions cannot be willed away," Ringholz said.